import random
class Rnb:
    @classmethod
    def number(self,a=10,b=50,num=20):
        return random.sample(range(a,b),num)

class PrintMinxi:
    def print(self):
        d = {self[i]:self[i+1] for i in range(0,len(self)-1,2)}
        for k,v in d.items():
            print("{},{}".format(k,v))

class Output(PrintMinxi,Rnb):
    pass

Output.print(Rnb.number())

# 完成的不错